Is my off-grid home suitable for a heat pump?

Heating our homes makes up 14%[1] of the UK’s carbon emissions, so as we all move towards a lower carbon future, it’s no surprise that we’re being urged to reduce our reliance on fossil-fuelled boilers. This is particularly true for homes off the mains gas grid, as they are typically older, less energy efficient and use more heat.

The government plans to phase out traditional boilers over the coming years, and it is now actively incentivising people to transition towards greener alternatives. Through its Boiler Upgrade Scheme[2], it’s offering homes £5,000 grants to put towards installing heating pumps, as well as other low carbon heating systems. In fact, it hopes to be installing 600,000 heat pumps a year by 2028.[3]

Heat pumps are an efficient renewable technology, and they will of course play an important role as the country journeys to net zero emissions. However, anyone considering switching to heat pumps needs to be aware that you need the right conditions and requirements for installation to get the best results.

For example, they work best in highly insulated, airtight properties; they need to be matched with low temperature radiators or underfloor heating; they need to be kept on consistently; and you need to have enough space inside and out to accommodate them. Admittedly, they’re not the perfect solution for everyone. In fact, a recent report from the Energy and Utilities Alliance suggests they could potentially be impractical for up to 54%[4] of UK homes.

So, how do you know if heat pumps are the right fit for your off-grid home? We’ve taken a look at the key factors you need to consider before investing in a heat pump, and also looked at how heat pumps compare with LPG (and soon-to-come Bio-LPG), which could be a more effective and lower cost option for some off-grid homes looking for a greener heating solution.

What is a heat pump?

First, let’s look at what an air source heat pump is, as this is still a relatively new technology to most UK homeowners. Heat pumps look similar to an air conditioning unit, and they sit outside of your property. They work like a fridge but in reverse, taking heat from the air outside, boosting it to a higher temperature using a compressor, and then transferring it indoors to heat your radiators or underfloor heating. Remaining heat is stored in your hot water cylinder that you can then use for showers, baths and taps. The pump and compressor run on electricity, but if your heat pump is installed in the right conditions, they should use less energy than the heat they produce, making them an energy efficient solution.

Is your home insulated enough?

For a heat pump to work effectively, your home must be properly insulated. Heat pumps operate at lower temperatures than traditional heating systems, which means they can take longer to get rooms to temperature if they’re draughty and letting out lots of heat.

Britain has some of the least energy efficient housing in Europe[5], and for homes to become suitable for heat pumps, significant upgrades may be required. Around 25 million[6] homes do not have adequate insulation, and to bring a poorly insulated home up to scratch could cost thousands.

This may be a particular concern for off-grid properties, as rural homes are typically old and less energy efficient, making them more challenging to upgrade. For example, oil-heated homes are more likely to have solid walls, which are harder to insulate to a good standard. Solid wall insulation can cost anywhere between £5,000 and £11,000[7], and it can impact a home’s appearance, which can make it unattractive to homeowners.

Do you have the right radiators?

Because heat pumps operate at a lower temperature, they should be paired with low temperature radiators or underfloor heating. Unlike boilers, which switch on and off and let you heat a space very quickly, heat pumps are meant to stay on 24/7 – providing a comfortable and consistent ambient temperature. However, this does mean it can take longer to heat up your home. Conventional boilers will heat the water in your radiators up to 75°C, whereas a heat pump will ideally circulate hot water to radiators or underfloor heating at temperatures of between 35°C -45°C[8], when working at its most efficient mode.

If you don’t already have compatible low temperature radiators, you’ll need to factor this into the installation and cost.

Do you have the space?

Not all homes have adequate space for an air source heat pump. First, you need to be able to fit the unit outside, which may not be possible if you’re living in a flat or a terraced house with limited outdoor space. For it to effectively extract heat from the air, it needs to be in the right spot, with plenty of air flowing around it, plus it needs to be accessible for maintenance too. Some heat pump models can also be noisy when they’re working, so it’s worth considering the impact that it could have on you and your surroundings.

You’ll also require indoor space as well. Unlike boilers, which provide hot water on demand, with heat pumps, heat is stored in a hot water cylinder until it is needed. This means you’ll need to accommodate this hot water cylinder too, which can be challenging in smaller properties.

What’s the cost of the installation?

An air source heat pump can cost anywhere between £7,000 and £14,000[9] and costs can vary based on the system and complexity of the installation. It is a big investment for people, and that’s why the government is offering 90,000 homes in England and Wales grants of £5,000 as part of its Boiler Upgrade Scheme. As mentioned, you may also need to add on the cost of upgrading your home to this figure, to cover any insulation, double glazing, bigger radiators, or underfloor heating.

Would LPG/Bio-LPG be a better fit?

Heat pumps aren’t for everyone, and if you’re concerned about the suitability for your home, or the cost, then liquefied petroleum gas (LPG) and soon-to-come Bio-LPG (renewable green gas) could be the perfect solution for you.

Unlike heat pumps, LPG provides instant high temperature heating and hot water, which means it can be a more effective solution for harder to treat off-grid properties. Modern LPG boilers are efficient and relatively low cost, plus you may not require extra upgrades like insulation or low temperature radiators. You won’t need space for a hot water cylinder, and you won’t need to worry about any unwanted noise. 

LPG is cleaner and greener than other conventional off-grid fuels. In fact, if you’re currently running on oil, and have an ageing boiler, then you could make significant cost and carbon savings by making the switch. LPG produces 20%[10] fewer carbon emissions than heating oil and far fewer other nasty pollutants that impact air quality.

But if you’re looking for a renewable fuel, there’s good news. Bio-LPG is a lower carbon version of LPG. Once Bio-LPG is more readily available, you’ll be able to just drop this eco-friendly green gas into your existing LPG system without needing to make any changes or buy any new equipment. This means anyone running on LPG now, is perfectly set up for a renewable future.

Want to find out more? Contact our energy experts on 0800 023 23 32 or get a quote today.










[10] BEIS Greenhouse Gas Reporting: Conversion Factors 2019